Dear all,
So far I have received more than a dozen responses. I still don’t know exactly what caused the noise; however, I have got what I want. I worried much about our whistling magnet before (I described this as hissing in my previous post, due to my English expression), but now I feel relieved, because three other ammrl members have had the similar experience with the Magnex magnets during LHe refilling. I would take this whistling as normal right now. Thank you very much for your inputs.
Guangyu
收件人: ammrl_at_ammrl.org
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主题: AMMRL: mysterious hissing from magnet
Dear all,
Yesterday during Helium refilling a hissing sound came from our 500MHz Magnex magnet installed 13 years ago. It was not loud but could be heard clearly. It lasted for several minutes. The lock signal was ok, shimming was good and the hissing was not related with the lifting gas, anti-vibration legs or VT system.
I searched ammrl mailing archives and found a mail telling the similar story, but the problem was not solved.
http://www.ammrl.org/archives/December-2003/18.html
I checked our helium refilling log and found the boil off rate just fine. After refilling the nmr system is working well. But I am still puzzled by the phenomenon.
Any ideas or experience highly appreciated!
Guangyu
Received on Sun Feb 16 2014 - 22:24:33 MST